After an indeterminate period of time, your web site may stop working with the following error:
Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.
This error is caused by SQL Connections being left open in the web site code. After a while a large amount of open sql connections will build up until a limit is reached and the web site stops working.
Ensure that all SQL Connections are closed after use. The recommended approach is to use the SQLConnection object within a Using statement. For example
Using conn as new SQLConnection
'Process queries here
SQLConnection objects need to be placed in a Using statement in addition to the SQLCommand object. Disposing the SQLCommand object may not close the underlying connection so SQLCommand.Connection also needs to be disposed.